re PR c++/53356 (ICE in verify_gimple_stmt, at tree-cfg.c:4258)

PR c++/53356
	* tree.c (stabilize_init): Handle stabilizing a TARGET_EXPR
	representing a bitwise copy of a glvalue.

From-SVN: r188029

gcc/cp/ChangeLog

@@ -1,5 +1,9 @@
 2012-05-30  Jason Merrill  <jason@redhat.com>
 
+	PR c++/53356
+	* tree.c (stabilize_init): Handle stabilizing a TARGET_EXPR
+	representing a bitwise copy of a glvalue.
+
 	* tree.c (stabilize_expr): Tweak logic.
 
 	PR c++/53356

gcc/cp/tree.c

@@ -3389,7 +3389,7 @@ stabilize_aggr_init (tree call, tree *initp)
    takes care not to introduce additional temporaries.
 
    Returns TRUE iff the expression was successfully pre-evaluated,
-   i.e., if INIT is now side-effect free, except for, possible, a
+   i.e., if INIT is now side-effect free, except for, possibly, a
    single call to a constructor.  */
 
 bool
@@ -3402,21 +3402,37 @@ stabilize_init (tree init, tree *initp)
   if (t == error_mark_node || processing_template_decl)
     return true;
 
-  if (TREE_CODE (t) == INIT_EXPR
-      && TREE_CODE (TREE_OPERAND (t, 1)) != TARGET_EXPR
-      && TREE_CODE (TREE_OPERAND (t, 1)) != CONSTRUCTOR
-      && TREE_CODE (TREE_OPERAND (t, 1)) != AGGR_INIT_EXPR)
-    {
-      TREE_OPERAND (t, 1) = stabilize_expr (TREE_OPERAND (t, 1), initp);
-      return true;
-    }
-
   if (TREE_CODE (t) == INIT_EXPR)
     t = TREE_OPERAND (t, 1);
   if (TREE_CODE (t) == TARGET_EXPR)
     t = TARGET_EXPR_INITIAL (t);
-  if (TREE_CODE (t) == COMPOUND_EXPR)
-    t = expr_last (t);
+
+  /* If the RHS can be stabilized without breaking copy elision, stabilize
+     it.  We specifically don't stabilize class prvalues here because that
+     would mean an extra copy, but they might be stabilized below.  */
+  if (TREE_CODE (init) == INIT_EXPR
+      && TREE_CODE (t) != CONSTRUCTOR
+      && TREE_CODE (t) != AGGR_INIT_EXPR
+      && (SCALAR_TYPE_P (TREE_TYPE (t))
+	  || lvalue_or_rvalue_with_address_p (t)))
+    {
+      TREE_OPERAND (init, 1) = stabilize_expr (t, initp);
+      return true;
+    }
+
+  if (TREE_CODE (t) == COMPOUND_EXPR
+      && TREE_CODE (init) == INIT_EXPR)
+    {
+      tree last = expr_last (t);
+      /* Handle stabilizing the EMPTY_CLASS_EXPR pattern.  */
+      if (!TREE_SIDE_EFFECTS (last))
+	{
+	  *initp = t;
+	  TREE_OPERAND (init, 1) = last;
+	  return true;
+	}
+    }
+
   if (TREE_CODE (t) == CONSTRUCTOR)
     {
       /* Aggregate initialization: stabilize each of the field
@@ -3439,11 +3455,6 @@ stabilize_init (tree init, tree *initp)
       return good;
     }
 
-  /* If the initializer is a COND_EXPR, we can't preevaluate
-     anything.  */
-  if (TREE_CODE (t) == COND_EXPR)
-    return false;
-
   if (TREE_CODE (t) == CALL_EXPR)
     {
       stabilize_call (t, initp);

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2012-05-30  Jason Merrill  <jason@redhat.com>
+
+	PR c++/53356
+	* g++.dg/init/new34.C: New.
+	* g++.dg/tree-ssa/stabilize1.C: New.
+
 2012-05-30  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/53356

gcc/testsuite/g++.dg/init/new34.C

@@ -0,0 +1,11 @@
+// PR c++/53356
+
+struct A { A(); ~A(); };
+
+struct B {
+    operator const A () const;
+};
+
+A* cause_ICE() {
+  return new A((A(),A()));
+}

gcc/testsuite/g++.dg/tree-ssa/stabilize1.C

@@ -0,0 +1,14 @@
+// PR c++/53356
+// { dg-options "-fdump-tree-gimple" }
+// { dg-final { scan-tree-dump-not "= 0" "gimple" } }
+// { dg-final { cleanup-tree-dump "gimple" } }
+
+class A {};
+
+struct B {
+    operator const A &() const;
+};
+
+A* cause_ICE() {
+    return new A(B());
+}